InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Two ice blocks of 10 g each are placed in 2 L distilled water at 273 K. One of theice blocks is made up of distilled water. What will you observe if the ambient temperature is also 273 K ? Give reasons to support your observation. |
| Answer» SOLUTION :After sometime one ice block will disappear and the otherone remains INTACT. The ice block which is made up of sea WATER melts because of lowering of melting point due to PRSENCE of dissolved SALTS. | |
| 2. |
Which separation techniques will you apply for the separation of the following ? (a) Sodium chloride from its solution in water. (b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride. ( c) Small pieces of metal in the engine oil of a car. (d) Different pigments from an extract of flower petals. (e) Butter from curd. (f) Oil from water. (g) Tea leaves from tea. (h) Iron pins from sand. (i) Wheat grains from husk. (j) Fine mud particles suspended in water. |
| Answer» Solution :(a) EVAPORATION, (b) Sublimation, ( c) Sedi mentation, (d) Chromatography, (e) Centrifugation, (f) SEPARATING funnel, (G) Filtration, (h) MAGNETIC separation, (i) Winnowing, (J) Centrifugation. | |
| 3. |
The teacher instructed three students 'A', 'B' and 'C'respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). 'A' dissolved 50g of NaoH in 100 mL of water. 'B' dissolved 50g of NaOH in 100g of water while 'C' dissolved 50g of NaOH in water to make 100 mL of solution. Which one of them has made the desired solution and why? |
| Answer» SOLUTION :The student 'C' has prepared the desired solution since it represents MASS/volume solution. The student 'A' has taken into ACCOUNT volume of the solvent while the student 'B' has considered the mass of the solution mass by volume % = `("Mass of solute")/("Volume of solution") xx 100 = (50)/(100) xx 100 = 50%` mass by volume. | |
| 4. |
What are impure substance? Give example. |
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Answer» Solution :IMPURE substance contain more than one kind of PARTICLES. EG. MIXTURES (Gum powder, which is a mixture of sulphur potassium nitrate and CHARCOAL) |
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| 5. |
Why are cotton clothes prefferred in summer ? |
| Answer» Solution :People wear COTTON clothes to KEEP themselves cool in summer. Cotton fabric absorb sweat more due to greater ahesive forces between cotton and water and also allows the sweat to be evaporated at a faster RATE. The sweat absorbs heat ENERGY equal to the latent heat of vaporisation from the body and gets evaporated, thus, keeping the body cool. | |
| 6. |
What is the effect of heat on the rate of diffusion? |
| Answer» SOLUTION :On HEATING the RATE of DIFFUSION INCREASES. | |
| 7. |
What is the mass of 1 mole of nitrogen atoms ? |
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Answer» SOLUTION :`N_(2) ` `(2 xx N) = 2 xx 14 = 28` mole = `28 xx 6.023 xx 10^(23)` |
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| 8. |
What is superphosphate of lime ? |
| Answer» SOLUTION :N/A | |
| 9. |
CHARACTERISTICS OF PARTICLES OF MATTER |
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Answer» Solution :The important characteristics of the particles of matter (like atoms or molecules) are the FOLLOWING : (i) The particles of matter are very, very small. (II)The particles of matter have spaces between them. (iii)The particles of matter are constantly MOVING. (iv) The particles of matter attract one ANOTHER. |
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| 10. |
The separation of denser particles from lighter particles done by rotation at high speed is calls _______ |
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Answer» FILTRATION |
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| 11. |
Which of the following is a (are) pure substances (s) ? |
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Answer» SUGAR |
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| 12. |
The valency of element E is 4, so the molecular formula of the chloride of this element is ........... . |
| Answer» SOLUTION :`ECl_(4)` | |
| 13. |
What are the limitations of J. J. Thomson's model of the atom? |
| Answer» Solution :According to Thomson.s model of the ATOM, ELECTRONS are embeded in a positively charged sphere. But the EXPERIMENTS carried out by other sctentists SHOWED that PROTONS are present only in the centre of the atom and electrons revolve around the centre. | |
| 14. |
X nelongs ot IA or first rop and fifth period and y succeedsX in the group .Z succeeds Y in the period Arrange the suitable statement in the correct sequence in order ot arrngeX,Y and Z in the incresing order of their atomic sizes |
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Answer» DBCA (ii) Determination of the NUMBER of shells and the number of valence elctrons present in x y and z (iii) Efect of the number of valence electrons and number of shells on ATOMIC size |
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| 15. |
Which seperation techniqueswill you apply for the Seperation of theSodium Chloridefrom its solution in water ? |
| Answer» SOLUTION : DISTILLATION | |
| 16. |
When water is heated to a temperature x, it gets converted into steam at temperature x by a process called R. And when steam at temperature x is cooled, it gets reconverted into water at the same temperature x by a process called S.(a)How much is the value of x in Kelvin ? (b) What is the process R called ?(c ) What is the name of the energy absorbed during the process R ?(d)What is process S known as ?(e)What is the name of energy released during the process S known as ? |
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Answer» |
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| 17. |
What are redox reactions? |
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Answer» |
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| 18. |
What are the different reactions taking place in fusion zone of blast furnace and explain how these reactions affect the temperature of the zone. |
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Answer» Solution :(i) REACTIONS associated with energy changes (ii) change in energy that is INVOLVED in the reactions taking place in fusion ZONE. (iii) effect of this change in energy on the termperature of this zone. |
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| 19. |
Which of the following belongto the same group? A^(3+) (number of electrons=10) B^(2+)(numberof electrons =10) C (number of electorns =5) D (numberof electorns=31) |
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Answer» ABC |
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| 20. |
Which among the following elements cause water pollution ? |
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Answer» MERCURY |
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| 21. |
Write equation for each conversion A to E. |
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Answer» Solution :`A""CaCO_(3)OVERSET(DELTA)toCaO+CO_(2)` `B""CaO+H_(2)OtoCa(OH)_(2)` `C""Ca(OH)_(2)+CO_(2)toCaCO_(3)+H_(2)O` `D""CaCO_(3)+H_(2)O+CO_(2)TOCA(HCO_(3))_(2)` `E""Ca(HCO_(3))_(2)overset(Delta)toCaCO_(3)+H_(2)O+CO_(2)` |
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| 22. |
What is the percentage of calcium in calcium carbonate (CaCO_(3)) ? |
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Answer» Solution :Molecular mass of `CaCO_(3) = 40+ 12 + 3 xx 16 = 100 ` amu . Mass of calcium in 1 MOL of `CaCO_(3) = 40`G `THEREFORE` PERCENTAGE of calcium = `(40 xx 100)/(100) = 40` . |
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| 23. |
Which of the following compounds is used as the raw material for many fertilisers? |
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Answer» `NH_3` |
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| 24. |
Water kept in an earthen pot becomes cool during summer. Which phenomenon is related with this process? |
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Answer» Diffusion |
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| 25. |
What are the components of a solution ? |
| Answer» SOLUTION :SOLUTE and SOLVENT are the COMPONENTS of a solution. | |
| 26. |
What will happen if these liquids are split on the floor? |
| Answer» SOLUTION :If these LIQUIDS are SPELLED on the FLOOR. They will FLOW. | |
| 27. |
What happens to the conductivity of metals with increase in temperautre ? |
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Answer» Solution :(i) change of MOVEMENT of meatal kernels with the increase in temperature. (II) CAUS of for flow of current throught metals (iii) changes in energy of metal kernels with temperature (iv) effect of movement of metal kernels in flow of eolectricity (v) RELATION between flow of electricity and conductivity. |
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| 28. |
When 3.00 g of carbon is burnt in 8,00 g of oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combination will govern your answer ? |
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Answer» Solution :`"CARBON + Oxygen" to "Carbon dioxide"` `C + O_(2) to CO_(2)` `12g + 32 g to 44 g` `:.` 3g of carbon BURNS in 8 g of oxygen producing 11 g of carbon dioxide. So, when there is 3.00 g of carbon and 50.00 g of oxygen, then also only 8G of oxygen will be used forming 11.0 g of carbon dioxide. 42 g of oxygen (50 g-8g) will remain unused. The answer is GOVERNED by the law of constant proportion. |
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| 29. |
What is chromatography ? |
| Answer» Solution :Chromatography is a technique USED to separate those SOLUTES of a MIXTURE which are soluble in the same solvent. It works on the principle of absorption. | |
| 30. |
What is the 3electronic configuration of Aluminium ? |
| Answer» SOLUTION :Electronic configuration ofAluminium atom : (Z= 13) K SHELL = , L shell = 8 and M shell = 3 electronic . So its electronic configuration is 2 , 8 , 3 | |
| 31. |
What are alpha particles ? |
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Answer» Solution :`alpha` - particles are doubly - CHARGED Helium ions with 4 units of MASS. These are PRODUCED from radioactive SOURCES like Radium or POLONIUM. `._(2)^(4)He to He^(2+)+2e^(-)` |
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| 32. |
What is the percentage of sulphur in sulphuric acid (H_(2)SO_(4)) ? |
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Answer» Solution :MOLECULAR mass of `H_(2)SO_(4) = 1 xx 2 + 32 + 16 xx 4 `= 98 amu `therefore ` percentage of SULPHUR = `(32 xx 100)/(98) = 32.65` |
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| 33. |
The volume of 1 mole of a gas at standard temperature and pressure is: |
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Answer» 11.2 LITRES |
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| 34. |
What is the mass of 4 moles of aluminium atoms (Atomic mass of aluminium = 27)? |
| Answer» Solution :`4 xx 6.023 xx 10^(23)xx 27 = 108 xx 6.023 xx 10^(23) ` atoms | |
| 35. |
Write the formula of the Magnesium phosphate |
| Answer» SOLUTION :MAGNESIUM PHOSPHATE `= Mg_3 (PO_4)_2` | |
| 36. |
What are the drawbacks of plastics? |
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Answer» Solution :Drawbacks of plastics (a) Plastics take a long time to fully break down in nature. (b) The microbes that breakdown plastics are too few and the QUANTITY of plastics we PRODUCE is too many. (c ) A lot of plastics does not GET recycled and ends up polluting the environment. (d) Some plastics contain harmful CHEMICAL additives that are not good for human health. (e) BURNING of plastics releases toxic gases that are harmful to health and environment (f) One time use and throwaway plastics end up littering and polluting the environment. |
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| 38. |
When a mixture of three miscible liquids is subjectedto fractional distillation, liquid B is obtained in the receiver flask. The remaining mixture on further fractional distillation, A, is left behindin the distillation flask. On the basis of the results, comment on the critical temperatures of A, B and Cwhen they are in gaseous state. |
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Answer» Solution :(i) relationbetween INTERMOLECULAR forces of ATTRACTION and boiling point (II) RELATION between critical temperature and boiling point (III) relation between intermolecular forces of attraction and boiling point (iv) relation between critical temperature and boiling point |
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| 39. |
What fraction of mass do neutrons contribute to carbon dioxide (CO_(2)) ? |
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Answer» |
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| 40. |
Which of the following is the gaseousprodcut obtained in roasting ? |
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Answer» `SO_2` |
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| 41. |
Which of the gases, oxygen and nitrogen will be separated first from liquid air ? Why? |
| Answer» SOLUTION :Nitrogen GAS will be separated first from liquid air. The boiling POINT of nitrogen is lower than that of oxygen. | |
| 42. |
What is meant by an irreversible reaction ? Give an example. |
| Answer» | |
| 43. |
Water is a compound. Explain. |
| Answer» SOLUTION :Water is made up of HYDROGEN and oxygen which are perseon in fixed proportion and the PROPERTIES of water are entirely DIFFERENT form its constituents, hence, it is a compound. | |
| 44. |
Three elements A,C and C have successitive atomic number in incresing order .A attains stability when an electorn is added to thee third shell which is the valecne shell .Identify A,B and c and predict the respective elements possessing the maximum ionisation energy oxidizing power reducing power electrons affinity and atomic size |
Answer» Solution :ASA attains STABILITY by gaining an elctron it must form a uninegativbe ion the third shell being the valence shell of a the elctronic configuration ofais 2,8,7 so the atomic numbr so the atomic number of B is 18 and that of c is 19. A,B,and C are CHLORINE argon and potassium respecitivley  Since CI has the highest elecrton affinity it gains an electron and attains stability thus it has greater oxidizing power.K which belongs to the IOA(1)group and 4th period possesses greater atomic size lower ionisation potential and greater reducing power .atomic size GRADUALLY increases form CI to k Ar which belongs ot hte 18th group possesses maximum ionisation potential due to a stable octet configuration |
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| 45. |
Which process will you use to separate a mixture of salt and ammonium chloride ? |
| Answer» SOLUTION :I will USE the PROCESS of SUBLIMATION. | |
| 46. |
What is absorption? Give example |
| Answer» Solution :ABSORPTION is the process in which the substance is dissolved throughout the bulk of another substance. EG. Paper SOAKS up or absorbs water. | |
| 47. |
Which postulate of Dalton.s atomic theory is the result of the law of conservation of mass ? |
| Answer» Solution :ATOMS are INDIVISIBLE particles, which cannot be created or DESTROYED in a CHEMICAL REACTION. | |
| 48. |
What is the number of molecules in 8g CH_(4)? |
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Answer» SOLUTION :Given mass of `CH_(4)` = 8 g, MOLAR mass of `CH_(4) = 12 + (4 xx 1)` =12 + 4 =16g The number of molecules = `("given mass")/("molar mass") xx "AVOGADRO number"` `=(8)/(16) xx 6.022 xx 10^(23)` `= 3.011 xx 10^(23)` The number of molecules in 8 g `CH_(4) = 3.011 xx 10^(23)` |
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| 49. |
What type of mixtures are separated The concentration of the solution at the given by the technique of crystallisation ? |
| Answer» Solution :The technique of crystallisation is used (i) to PURIFY salt obtained from sea water (II) to SEPARATE crystals of SOLIDS from impure samples. | |
| 50. |
To verify the law of conservation of mass in a chemicl reaction four students A,B,C and D perfored the following chemicla reactions in the schoold laboratory. Added zinc granules to dil hydorchlorica acid (b) heated lead nitrate (solid) in a test tube (c ) dipped mg ribbon in copper suphate solution (d) added barium chloride solution to sodium suphate solution . Which student according to you islikely to obtain the best results and why? |
| Answer» SOLUTION : student (D) is likely to obtain the best RESULT because the reaction is completed immediately and a white PRECIPITATE is FORMED | |